defexcludeEndsWith: List[String]

defexcludeNames: List[String]

defexcludeStartsWith: List[String]

defexecute(id: String): Option[Any]

What to return if this completion is given as a command.

What to return if this completion is given as a command. It
returns None by default, which means to allow the repl to interpret
the line normally. Returning Some(_) means the line will never
reach the scala interpreter.